BaBiO3, a perovskite contains two kind of valences Bi3+ and Bi5+. The xps analysis shows two peaks for Bi that confirms the dual valence of Bi in BaBiO3. Some researchers propose that the peak at higher binding energy belongs to Bi5+ and the peak at lower binding energy belongs to Bi3+. Can anyone tell me the exact binding energy for Bi3+ and Bi5+?
The exact binding energy will vary based on the surrounding atomic composition of the targeted Bi to measure. There can not be any absolute value. It is true that if more positive charge is surrounding the Bi as in Bi 5+ more energy will require to detach the binding electron so the binding energy of Bi 5+ will be more than that of Bi 3+. There is no exact as it will vary from compound to compound
The exact binding energy will vary based on the surrounding atomic composition of the targeted Bi to measure. There can not be any absolute value. It is true that if more positive charge is surrounding the Bi as in Bi 5+ more energy will require to detach the binding electron so the binding energy of Bi 5+ will be more than that of Bi 3+. There is no exact as it will vary from compound to compound
The exact binding energy will vary based on the surrounding atomic composition of the targeted Bi to measure. There can not be any absolute value. It is true that if more positive charge is surrounding the Bi as in Bi 5+ more energy will require to detach the binding electron so the binding energy of Bi 5+ will be more than that of Bi 3+. There is no exact as it will vary from compound to compound
There is no specific answer as the binding energy depends on the individual compound (and this is where the literature values and correction factors come from). Oxidation states are normally calculated by assuming 285 eV for carbon (and correcting an observed value for this - so if you're seeing the carbon peak at 287 then 2 eV is subtracted from all the other peaks to correct for charging). If we assume no charging then the oxidation sate is then calculated from the displacement from the given literature value for the appropriate bismuth metal peak. So if the literature Bi metal 4f 5/2 peak is at 162 eV then you'd expect Bi3+ at 165 eV and Bi5+ at 167 eV. Accordingly for the Bi 4f 7/2 peak (157.5 eV?). Not sure what you mean by "Some researchers propose that the peak at higher binding energy belongs to Bi5+ and the peak at lower binding energy belongs to Bi3+". I do not think that there would be any doubt about this - higher BE's = higher oxidation states.
Dear Alan F Rawle and Sabyasachi Sarkar Thanks for your reply.
Dear Alan F Rawle, I will explain my question again. The xps analysis of BaBiO3 shows a doublet peak for Bi due to presence of Bi3+ and Bi5+. For example Bi 4f 7/2 splits into two peaks one is 157.5 eV and other is 158.4 eV. I have attached the (G. P. Kostikova et al.) reference article here. According to this reference the binding energy 157.5 represents Bi5+ and the biding energy 158.4 represents Bi3+. So according to this reference the peak at higher binding energy is for Bi3+ and peak at lower binding energy is for Bi5+. Now my statement "Some researchers propose that the peak at higher binding energy belongs to Bi5+ and the peak at lower binding energy belongs to Bi3+". I have attached another reference (Mark A. Hughes et al.) here. So these results are contradictory. I want to know the exact rule for assigning the binding energies to Bi in different oxidation states. Of course the exact values of binding energies vary for different environments.
I am sorry to state that there is no rule but basic logic. To remove electron from more positive field requires more energy compare to from lesser positive field. So the binding energy of Bi(+5) will be more than from Bi(+3).. This is fundamental law of electrostatic interaction. If some publication says reverse then either that is a misprint or wrongly written
In a compound material especially an oxide the binding energies of Bi(+5) and Bi(+3) are bound to vary due to chemical shift.
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